Method for preparing alpha, omega-dihaloalkanes



y s ,$142,708 Vl- Patented July 28, 1964 nite States tei diluent orsolvent inert under the conditions of the 3,142,708 reaction such astetrachloroethylene, dichloromethane,

METHOD FOR PREPARING ,w-DIHALOALKANES John Douglas Young, Lake Jackson,Tex., assignor to The Dow Chemical Company, Midland, Mich., a corpora-1,2-dichloroethane, trichlorobenzene or the respective fluoro compoundswhen employing sulfuryl fluoride, sultion of Delaware furyl iodide orsulfuryl bromide, respectively, to obtain N0 Drawing. Filed Aug. 15,1961, Ser. No. 131,502 the fluoroalkane, iodoalkane or bromoalkane,respec- 3 Claims. (Cl. 260-653.1) tively.

l Various free-radical-forming initiators are useful in Thepresentmventlon relates, to a novel method for effecting the reaction. Some ofsuch include the organic preparing ,w-dihaloalkanes having the generalformula: 20 peroxides Le benzoyl peroxide, acetyl peroxide, (L butylX(C2H4)nX peroxide, t.-butyl peracetate, t.butyl perbenzoate, succinnicperoxide, diisopropyl percarbonate and the like, as well as abisisobutyronitrile, triphenylchloromethaiie 0r tetraethyllead. Anysource of gamma irradiation may also be used.

The following examples illustrate the present invention but are not tobe construed as limiting:

wherein n represents an integer of at least 2 and X represents a halogenhaving an atomic number from 9 to 53. In accordance with the presentinvention an a,wdihalo alkane can be prepared by reacting ethylene withsulfuryl halide in the presence of a free-radcal-forming agent such asorganic peroxide or any other well known free-radicalforming initiator,including gamma irradiation, at a temperature of from about to 300 C.and a pressure of from 1000 PSig to abou-t 30000 psi'g' for fromEthylene under 10,000 p.s.i.g. pressure and heated to ltpesetnomingdoghleoe about C. is introduced simultaneously with a solution iscarried out at a temperature of from about to non of suifuryl chlorifleand benzoyl peroxide in metilyl- 230 C. at a pressure of from about 6000to 10,000 p.s.i.g. ene Chlollde or IZ'dlchloroethane cooled to 9 mto andthe reactants are employed in a ratio of from 1 to 35 a feed mixerattached to a tubular reactor maintained at about C. by externalcooling. Various feed rates 1000 moles of ethylene per mole of sulfurylhalide. The v preferred ratios are from 10 to 50 moles of ethylene andand various compositions of the sulfuryl chloride solution Example 1from 0.001 to 0.0003 mole of free-radical-forming initia- 0f each 0f theabove Were employed t0 Obtain dlffelent tor per mole of sulfufyl halide,40 residence times in the reaction and the results are tabu- Thereaction can be carried out in the presence of a lated below:

Mole percent in Feed Products, Mole Percent Pressure Residence MoleReactants p.s.i.g. Temp., Time, Percent X103 C. Seconds SOgClg EthyleneSolvent, Chloride Catalyst 1 Conver- Chloride DCB 4 DOH 6 SulfurylEthylene sion Chloride Methylene:

7. 7 75. 9 04 3 150 25 22 87. 0 12. 4 0. 6 4. 4 69. 9 03 3 156 2l 95 80.6 18. 5 0. 8 2. 8 7S. 0 02 3 155 23 94 73 8 24. 7 1. 5 0. 7 64. 9 004 3145 19 75 45 1 50. 6 4. 3 0. 4 76. 4 002 3 146 2l 65 27 7 65. 3 6. 9 5.4 67. 8 03 4 147 2l 36 76 7 2l. 2 2. 1 1. 1 79. 0 006 4 155 22 65 40 656. 5 2. 9 6. 3 62. 9 014 4 196 56 74 50. 4 45. 8 3. 7 1l. 1 65. 5 005 4246 50 60 65. 0 33. 7 1. 3

1 Benzoyl peroxide except as indicated in footnotes 2 and 3. 2 Triphenylchloromethane.

5 Acetyl peroxide.

4 Diclilorobiitane.

5 Dichlorohexane.

I claim: 1. A method for preparing ,w-dihaloalkanes having the generalformula X(C2H4)nX wherein n represents an integer from 2 to 10inclusive, and X represents a halogen having an atomic number from 9 to53, which comprises reacting ethylene with sulfuryl halide in thepresence of a free-radical source at from about 100 to 300 C. and at apressure of from about 1000 to 30,000 pounds per square inch for fromabout 5 10 2,440,800

seconds to about 10 minutes.

2. The method of claim 1 wherein from 1 to 1000 moles of ethylene areemployed per mole of sulfuryl halide.

3. The method of claim 1 wherein a peroxide catalyst iS employed in anamount of 0.1 to 0.00005 mole per mole of sulfuryl halide.

References Cited in the file of this patent UNITED STATES PATENTSHanford et al. May 4, 1948

1. A METHOD FOR PREPARING A,W-DIHALOALKANES HAVING THE GENERAL FORMULA